Nitro-2,2,4-trimethylpentane

Submitted by Nathan Kornblom and Willard J. Jones.1 Checked by William G. Dauben and Paul R. Rf.snick. 

A solution of 25.8 g. (0.20 mole) of 4-amino-2,2,4-trimethyl-pentane (ierf-octylamine) (Note 1) in 500 ml. of C.P. acetone is placed in a 1-1. three-necked flask equipped with a Tru-Bore stirrer and a thermometer and is diluted with a solution of 30 g. of magnesium sulfate (Note 2) in 125 ml. of water. Potassium permanganate (190 g., 1.20 moles) is added to the well-stirred reaction mixture in small portions over a period of about 30 minutes (Note 3). During the addition the temperature of the mixture is maintained at 25-30° (Note 4), and the mixture is stirred for an additional 48 hours at this same temperature (Note 5). The reaction mixture is stirred under water-aspirator vacuum at an internal temperature of about 30° until most of the acetone is removed (Note 6). The resulting viscous mixture is steam-distilled approximately 500 ml. of water and a pale-blue organic layer are collected. The distillate is extracted with pentane, the extract is dried over anhydrous sodium sulfate, and the pentane is removed by distillation at atmospheric pressure. The residue is distilled through a column (Note 7) at reduced pressure to give 22-26 g. (69-82%) of colorless 4-nitro-2,2,4-trimethylpentane, b.p. 53-5473 mm., 1.4314, m.p. 23.5-23.7°. 

The /erf-octylamine employed was redistilled commercial-grade material, b.p. 140°/760 mm., 1.4240. 

The magnesium sulfate was purified dried powder of J. T. Baker Chemical Co. This is approximately 70% magnesium sulfate and 30% water. 

Good agitation prevents the permanganate from caking on the bottom of the flask. The formation of a cake results in local overheating and consumption of the permanganate as mentioned in Note 4. 

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The procedure described is that of Komblum, Clutter, and Jones.2 4-Nitro-2,2,4-trimethylpentane has been prepared previously, in low yield, by allowing isooctane to react with concentrated nitric acid in a sealed tube at elevated temperature.5... 

The oxidation of some aliphatic amines is a good route to aliphatic nitro compounds. tert-Butylamine is oxidized in 83% yield to 2-methyl-2-nitropropane by potassium permanganate in water at 45 °C for 8 h and at 55 °C for 8 h [738, 892], Under similar conditions, 4-amino-2,2,4-tri-methylpentane is converted into 4-nitro-2,2,4-trimethylpentane in 69-82% yields [859]. Refluxing 3a-acetoxy-20a-amino-5p-pregnane with a chloroform solution of m-chloroperoxybenzoic acid for 40 min furnishes 3a-acetoxy-20a-nitro-5p-pregnane in 66% yield [379]. 2-Aminobutane is converted into 2-nitrobutane by peroxyacetic acid [253] or dimeth yldioxirane [277] (equation 498). 

NaBH4 added slowly to a soln. of l-nitro-2,4,4-trimethyl-2-pentyl nitrate in 95%-ethanol, stirred briefly at room temp., and allowed to stand for 2.5 days -> 1-nitro-2,4,4-trimethylpentane. Y 83%. F. e. s. J. M. Larkin and K. L. Kreuz, J. Org. Chem. 36, 2574 (1971). 

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